1. Field of the Invention
The present invention relates generally to liquid filtering apparatuses, and, more particularly, to a portable liquid filtering apparatus for use with deep fat fryers.
2. Description of the Related Art
Cooking oil is extensively used in the food industry to cook various comestibles. Animal fat or other suitable material may sometimes be used as the cooking material in lieu of cooking oil. The term “cooking oil” is used herein to designate any such material.
Frying is frequently accomplished in relatively deep containers with the comestible to be cooked immersed in the cooking oil. In cases where quantities of food are regularly cooked in such a manner, the cooking oil becomes contaminated with various particles of food or other impurities, and charred food particles produce an odor, which adversely affects the taste of foods cooked therein.
Wire mesh strainers have been long known and used to remove particulate matter from cooking oil. Strainers have not been effective, however, to remove sufficient particulate matter to provide particulate-free cooking oil, and have been demonstrated to only slightly prolong the usefulness of the cooking oil. To beneficially control free fatty acids in the cooking oil, suspended particles of the size of two (2) microns and larger should be removed from the cooking oil.
Conventional systems and apparatus for filtering cooking oil require that the cooking operation be interrupted to filter the cooking oil or to clean continuous filtering systems. A disadvantage of conventional methods of filtering cooking oil is that such methods require that the cooking operation be ceased during the period that the cooking oil is filtered. This results in significant downtime.
Overbeck, U.S. Pat. No. 2,635,527, discloses a deep frying strainer to be located at the bottom of the cooking oil container to strain food particles from cooking oil as the strainer is lifted from the container and the liquid is forced through the strainer by the action of gravity. Although beneficial to remove much particulate matter, the invention disclosed does not effectively remove smaller particulate contaminants.
U.S. Pat. No. Re. 34,636, reissued on Jun. 14, 1994, to the present inventor, describes a cooking oil filtering apparatus which can be used to effectively remove particulates from the cooking oil. Such particulates may include coatings from fried objects, seasonings and the like. The cooking oil is drawn through wire mesh screens by applying suction at the filter interior. As the cooking oil is drawn to the wire mesh screens, the screen serves to remove particulates from the cooking oil. The particulate-free cooking oil is then drawn into an outlet and drawn through the tank to a pump. The pump passes the cooking oil back into the tank. This process is carried on until particulate matter is removed from the cooking oil. A filter powder may be dispersed in the cooking oil to accumulate on the outer surfaces of the wire mesh screens. The subject apparatus eliminated the need for filter paper.
U.S. Pat. No. 5,404,799, issued on Apr. 11, 1995, and U.S. Pat. No. 5,486,370, issued on Jan. 23, 1996, both to the present inventor, describe cooking oil filtering apparatuses and methods which can be used to effectively remove particulates from the cooking oil. While effective, these apparatuses and methods require a specific fryer system, or mechanical modification of an existing fryer system.
Miles, et al, U.S. Pat. No. 2,760,641, discloses a portable filtering apparatus for use in cleaning cooking oil or other liquids. According to the Miles, et al. disclosure, the contaminated cooking oil is first drained from the cooking reservoir into a draw-off container. The filter is then submerged in the oil in the draw-off container. The oil is then pumped by the pump motor through the filter and pump. The pump discharges the oil through a discharge tube and into the cooking reservoir. This apparatus does not permit cleaning the cooking oil while it is still in the cooking reservoir, or cleaning the oil while cooking.
Not shown is a truly portable liquid filtering apparatus that permits filtering liquids in the same container in which they are used or stored. Nor a a portable filtering apparatus will permit filtering the liquids without downtime for cooling such liquids. Nor an apparatus that will further reduce downtime by allowing the liquid to be filtered while it is in use, such as during the cooking of foods therein.